1. Field of the Invention
The present invention relates generally, to electrical control systems. More specifically, the invention relates to wireless systems activated by a coded key card for energy management and/or control of line-powered devices.
2. History of the Prior Art
It is commonly difficult, costly and/or impractical to install wires between existing controlled electrical systems/circuits and new controlled electrical device(s). The level of difficulty and/or impracticality may be attributable to the need to damage or demolish ceilings, floors, or walls, in order to run control wires. Labor costs for installing new wiring can be considerable. This is particularly true if a team of electricians is required to perform the job.
As a wireless alternative to installing new wiring does not suffer from the aforesaid disadvantages, such an alternative may be advantageous if the utility of the wired and wireless solutions are substantially equivalent. In fact, a wireless control system may confer additional capability and/or convenience compared to hard-wired systems. Various methods and/or systems have been proposed, which attempt to overcome some of the difficulties/impracticalities mentioned above (see reference patents). Unfortunately, these methods fall short of addressing the wide variety of circumstances which may be encountered when designing, installing, deploying, and commissioning such systems. Moreover, they do not allow for flexibility in connecting to or interfacing with other systems. Further, they are restricted to specific applications or installation scenarios. Further still, their system architectures do not allow the system to be easily scaled up or down, as system needs evolve or change. In fact, they may even require ongoing maintenance, much of which can be eliminated.
One particular application involving wireless communication involves the use of a key card generally having the rectangular shape and dimensions of a typical credit card, which are 54 mm×86 mm, or about 2⅛ inches×3⅜ inches. The key card is inserted in a slot of a key card holder/detector that is typically mounted to an interior wall of a hotel room. When a key card is inserted in the holder/detector, a first signal is sent to a control circuit, which can perform one or more functions, such as turning on lights, turning on a heating/air conditioning system, activating a TV system. When the key card is removed from the holder/detector, a second wireless signal is sent to the control circuit, which then typically performs reverse functions, such as turning off the lights, turning off the heating/air conditioning system, and deactivating a TV system. The primary function of prior art key card holder/detectors is to lower energy costs for the hotelier by minimizing energy consumption in the room when guests are not present. Because early key card holder/detectors were hard wired, their use was primarily limited to new construction, as installation of these devices in an already completed structure required the running of wiring through the walls. Although the latest key card holder/detectors use wireless signals to communicate with the control circuit, they have several significant drawbacks. The first is that the signal that is sent is indicative only of either the presence or absence of a key card. The second is that the prior art key car holder/detectors works with any plastic card having the standard 54 mm×86 mm dimensions, whether it be a key card, credit card, customer loyalty card, etc. Thus, the function of the key card holder/detector can be easily defeated by inserting a non-key card into the holder/detector when the guests leave the room, thereby overriding the energy saving function of the device.